Thermoregulation and body temperature of the sable Martes zibellina (Mustelidae) in Yakutia during the cold period

In Yakutia, sable is represented by two forms, the wild and farmed. The wild sable is widespread in its natural habitat and populates the entire taiga zone of Yakutia. The farmed was imported to the fur breeding farms of Yakutia from European Russia and southern Siberia. Current research into the biological characteristics of sables and other marten species covers all aspects of their life. However, the study of their environmental and physiological characteristics is relatively limited. In the present work, the main components of thermoregulation of these animals, namely body temperature, oxygen intake and behaviour at temperatures up to -50 °С in the conditions of Yakutia are submitted. These parameters were for the first time comprehensively characterized based on comparative observations of farmed and wild sables. The aim of the research was to study the environmental and physiological mechanisms of the cold adaptation of farmed sables transferred to Yakutia and compare them with the heat exchange of local sables captured in natural habitats within the region. The research was carried out in 2023-2024. Six sables, three raised in captivity (outside Yakutia) and three from Yakutia natural populations, were used to assess oxygen consumption, four animals for behavior study, and two ones were involved in year-round assessment of body temperature.. Caged (farmed) sables were kept at the Pokrovskaya Zoo Farm LLC. The animals from natural populations were also contained at this farm. IP video cameras HI-IPA400F20 5mpx 2.8 mm (HIVIDEO, China) were used to observe animal behavior. When analyzing video recordings, the following types of behavior were distinguished: staying in the insulated house for more than 1 min; staying in the enclosure in an active state (movement, feeding); staying in the enclosure in a passive state (sleeping, resting). Thermoregulation in sablefish was evaluated based on the study of oxygen consumption using the open system technique. Gas analysis was performed using the gas analyzer IGS-98 Kometa-M (AnalytTeploKontrol LLC, Russia). In total, more than 250 measurements of oxygen consumption of six individuals in the temperature range from -30 to 30 °С were analyzed. The body temperature of the animals was measured using a DS 1922 L-F5 temperature recorder (Engineering Technologies, Russia). The thermorecorder was implanted in the axillary region under general anesthesia in a veterinary clinic. The frequency of measurements was 1 measurement per 60 min, and the ambient temperature was measured simultaneously. After 1 year, the device was removed and the results were statistically processed. The results showed that farmed and wild sables responded similarly to changes in ambient temperature. The optimum temperature zone was in the same range for all animals (+20 °С to +3-5 °С), metabolic growth occurred up to 5-20 °С, and its intensity did not differ between animals. From January to June, the average daily body temperature gradually increased, from July to August it decreased, reaching the minimum values (+36.8±0.03 °С, n = 744, from +33.9 °С to +38.5 °С) in January-February. In summer, the body temperature of sables remained relatively high (+37.2±0.02 °С, n = 744; from +34.9 °С to +38.8 °С), and its changes during the day followed the variability of the ambient temperature. In winter, there were no pronounced differences between day and night temperatures. Observations of animal activity in the enclosures from June to December revealed an increase in the duration of stay of sables in insulated houses with decreasing ambient temperature, probably for minimizing energy consumption. Oxygen consumption in the studied sables in the zone of optimal temperatures averaged 1.07±0.11 ml/(g·h), minimum 0.67 ml/(g·h), maximum 1.53 ml/(g·h). The maximum oxygen consumption at 15-20 °С was 1.34±0.13 ml/(g·h), 0.99-1.78 ml/(g·h). The growth rate of oxygen consumption was on average 0.21±0.05 ml/(g·h) per 1 °С. The data obtained on a number of indicators of sables born in captivity in different regions of Russia show similarities and differences with similar indicators of animals from natural populations of Yakutia. Similarities are noted in the behavior of animals and metabolic reactions to changes in ambient temperatures. The general direction of the annual dynamics of body temperature in the farm sable was also similar to that of animals from the natural population, but had significant differences in the values of absolute and average variability of temperature dynamics.